Two novel delta-endotoxin gene families cry26 and cry28 from Bacillus thuringiensis ssp. finitimus.

Genes cry26Aal and cry28Aal were cloned from Bacillus thuringiensis ssp. finitimus strain B-1166 VKPM. This strain forms insecticidal crystal bodies either outside or inside the exosporium. The deduced amino acid sequence of the cry26Aal gene product included seven residues determined to be an N-terminal part of a chymotrypsin-treated delta-endotoxin isolated from the same strain. Earlier this protein was detected in both free and spore-associated types of crystals [Revina et al., Biokhimia (1999) in press]. Neither BtI nor BtII promoter sequences were found upstream of the open reading frames in both genes. Southern hybridization has shown that the surroundings of both genes at least 3 kb upstream and downstream of the open reading frames are unique. We suggest that the protein Cry26Aal in both types of crystal bodies is synthesized under the control of one and the same genomic locus.